The invention pertains to warning devices of the unauthorized entry type utilizing compressed air to produce an audible signal upon the opening of a building closure.
With the present high crime rate, much concern has been expressed as to the unauthorized entry of buildings and motel and hotel rooms for the purpose of theft or assault. A number of safety devices have been proposed for preventing unauthorized entrance through doors and windows and such devices take the form of latches, locks, clasps, props, signals, etc. Of particular concern to the traveler has been the possibility of unauthorized entrance to occupied motel and hotel rooms.
The majority of burglar warning and deterring devices are of the passive type, i.e., are silent in operation and consist of locks, tamper-proofing devices, and the like. However, it is known to utilize active burglar alarm systems wherein audible and visual indicators are used to warn of the intrusion. Of course, burglar alarm systems for commercial buildings wherein police departments are automatically alerted are well known and smaller units have also been proposed for producing a warning signal of a localized nature, as shown by my U.S. Pat. No. 3,618,557.
In my aforementioned patent a bellows device is used to activate a vibratable reed upon the unauthorized opening of a building closure. The energy supplied to activate the device is that energy used to open the closure and, if the closure is very slowly opened, it is possible to prevent the signal from occurring or being produced in sufficient volume to be an effective warning. Other burglar warning devices which have been proposed rely upon batteries, and electric power sources which may be purposely rendered inoperative, or over a period of time deplete their energy and become inoperative and, to my knowledge, an effective self-powered burglar alarm is not available on the market which fully meets the desired criteria of such a device.